I've been using an Archos 70 8gb since the beginning of the year and I'm quite happy with it.
I've installed Google's Market on it, the Nook App, Sony's App, and an app called iReader that I can read my old DRM protected Mobipocket books with.
Screen isn't as crisp as my iPhone 4 or my wife's Nook but its very good. I even use it for comic book reading with the Android Comic Viewer and Comixiology.

Its been a great device so far.

Thanks for the feedback. I hope my experience will be as good.

One concern I have is the lack of astronomy apps. Only Google Sky for star maps. I am a star gazer and currently use my iPhone for my star maps and there are a lot of astronomy apps. I hope more will be developed over time.